In each IVF cycle, a decision must be made as to which embryo(s) will be selected for transfer. This decision has a far reaching impact on the outcome of an IVF cycle, namely whether the embryo will develop into a healthy child. It is estimated that at least 50% of human embryos are affected by chromosomal abnormalities such as aneuploidy, and implantation of such embryos can lead to undesired outcomes such as failed implantation, spontaneous abortion, or birth of a trisomic offspring. Reproductive specialists have been increasingly turning to pre-implantation genetic diagnosis (PGD) in efforts to identify embryos with the best chance of developing into healthy children. However, current techniques are expensive, unreliable and typically test only a small selection of chromosomes. GSN has developed an innovative technology termed Parental SupportTM (PS) whose output is an in silico reconstruction of the embryonic DNA at thousands of loci with confidence exceeding 99%. This technology will, for the first time, allow IVF physicians to screen embryos for chromosomal abnormalities including aneuploidy, translocations and deletions across all 23 pairs of chromosomes with an error rate below 0.1%. The Phase I objective of this application is to integrate our PS technology with a new, highly parallelized custom Infinium-based genotyping platform to dramatically reduce costs that will, in turn, enable GSN to offer PGD service with superior accuracy, scope and at a cost equivalent to current, less reliable FISH methods. The new customized platform will then be applied in Phase II where we propose to evaluate the concordance between a new trophectoderm biopsy technique on day 5, traditional blastomere biopsy on day 3, and the actual child. The results from these studies will allow us to assess the value of the new biopsy technique, evaluate the largely unstudied phenomenon of embryo self-correction between day 3 and day 5, and provide IVF physicians with powerful and far-reaching knowledge about the developmental potential of each embryo.